Highlighting sectioned apps on fast-scroll.

- This CL fixes an old assumption we had about the height
  of rows in AllApps, and ensures that we account for the
  difference in height between the predictive icons and the
  normal icons.
- In addition, we refactor FastBitmapDrawable to have multiple
  states, which it manages in drawing itself, including the
  press state and fast scroll focus states.  And we also refactor
  some of the fast scroll logic in the all apps recycler view
  out to its own class.

Change-Id: I1988159b2767df733bbbfc7dc601859cde6c9943

src/com/android/launcher3/BaseRecyclerViewFastScrollBar.java

@@ -27,6 +27,7 @@ import android.graphics.Path;
 import android.graphics.Point;
 import android.graphics.Rect;
 import android.view.MotionEvent;
+import android.view.VelocityTracker;
 import android.view.ViewConfiguration;
 
 import com.android.launcher3.util.Thunk;
@@ -37,7 +38,7 @@ import com.android.launcher3.util.Thunk;
 public class BaseRecyclerViewFastScrollBar {
 
     public interface FastScrollFocusableView {
-        void setFastScrollFocused(boolean focused, boolean animated);
+        void setFastScrollFocusState(final FastBitmapDrawable.State focusState, boolean animated);
     }
 
     private final static int MAX_TRACK_ALPHA = 30;
@@ -199,7 +200,7 @@ public class BaseRecyclerViewFastScrollBar {
                     }
                     mTouchOffset += (lastY - downY);
                     mPopup.animateVisibility(true);
-                    animateScrollbar(true);
+                    showActiveScrollbar(true);
                 }
                 if (mIsDragging) {
                     // Update the fastscroller section name at this touch position
@@ -210,7 +211,7 @@ public class BaseRecyclerViewFastScrollBar {
                             (bottom - top));
                     mPopup.setSectionName(sectionName);
                     mPopup.animateVisibility(!sectionName.isEmpty());
-                    mRv.invalidate(mPopup.updateFastScrollerBounds(mRv, lastY));
+                    mRv.invalidate(mPopup.updateFastScrollerBounds(lastY));
                     mLastTouchY = boundedY;
                 }
                 break;
@@ -222,7 +223,7 @@ public class BaseRecyclerViewFastScrollBar {
                 if (mIsDragging) {
                     mIsDragging = false;
                     mPopup.animateVisibility(false);
-                    animateScrollbar(false);
+                    showActiveScrollbar(false);
                 }
                 break;
         }
@@ -246,7 +247,7 @@ public class BaseRecyclerViewFastScrollBar {
     /**
      * Animates the width and color of the scrollbar.
      */
-    private void animateScrollbar(boolean isScrolling) {
+    private void showActiveScrollbar(boolean isScrolling) {
         if (mScrollbarAnimator != null) {
             mScrollbarAnimator.cancel();
         }